Flow regulating valve



Jan. 22, 1952 F. T. HARRINGTON 2,583,296

FLOW REGULATING VALVE Filed June 18, 1945 2 TS-SHEET 1 I mo INVEUTOR. l

l FERRIS T. HARRNGTON W A. W

ATTORNEY 1952 I F. T. HARRINGTON FLOW REGULATING VALVE 2 SHEETSShEET 2 Filed June 18, 1945 inllE INVENTOR. FERRIS T HARRINGTON ATTORNEY Patented Jan. 22, 1952 2,583,296 7 FLOW acoumrmo VALVE Ferris 'I. Harringtom Deti-oit, Mich., assignor to Vlckera Incorporated, Detroit, Mieln," a corporation of Michigan Application June 18, 1945, Serial No. 600,002

6 Claims.

This invention relates to power transmissions, particularly to those of the type comprising two or more fluid pressure energy translating devices, one of which may function as a pump and another as a fluid motor.

In particular, the invention relates to an improvement in a flow-regulating valve comprising an adjustable throttle and a compensating valve for maintaining a constant flow across the throttle through which fluid is adapted to flow at a regulated rate.

Flow-regulating valves have an important use in hydraulic power transmissions for driving machine tools. They serve the purpose of producing a reduced speed rate of the machine tool which may be driven by the fluid motor at a constant regulated rate of speed regardless of load resistance.

In the past in hydraulic transmissions containing a fluid motor used for the purpose of driving a machine tool and a flow-regulating valve to regulate the speed of the motor, some difliculty was presented in preventing motor jump when the motor was started after interruption and, in particular, when the machine tool slide connected to the motor was moved into a feed position from rest or where there was a resumption of a feed movement after interruption during a slide movement. If the operator oi a machine tool forgot to back the tool away from the work before resuming a out after a feed movement was interrupted, the tool was damaged because of this motor jump. This is due to thefact that. when flow through the flow-regulating valve is interrupted. the compensating valve is held to the fully open position by a compensating valve spring. When flow is resumed through the flow-regulating valve after interruption, a temporary flow of fluid above the amount the flow-regulating valve ordinarily would permit, passes through the fully open compensating valve before it is able to assume normal regulating position. Although this is only a momentary lapse and the compensating valve almost immediately assumes normal regulating position, this temporary flow of fluid above the normal regulated rate causes the motor to jump slightly before a constant regulated movement begins.

In the past this difficulty has been avoided by the addition of valves incorporated in the transmission to induce a flow through the flow-regulating valve or by means external to the flowregulating valve to close the compensating valve when flow through the flow-regulating valve was interrupted.

It is an object of this invention to provide an improvement in a flow-regulating valve containing an adjustable throttle and compensating valve which will prevent a flow of fluid above the normal regulated rate when flow is resumed after interruption through the flow-regulating valve.

It is also an object to provide an improvement in a flow-regulating valve as above mentioned for use in a hydraulic transmission containing a fluid pump and motor which will prevent motor jump when the motor is started after interruption.

It is a further object of this invention to provide an improved flow-regulating valve which will prevent motor jump when the motor is started after interruption, which may be economically manufactured, simple in operation, and which avoids the addition to the transmission of extra valves necessitating extra lines and fittings.

Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawings wherein a preferred form of the present invention is clearly shown.

In the drawings:

Figure 1 is a longitudinal sectional view of a preferred form of the present invention. 1 Figure 2 is a. simplified diagrammatic view of a hydraulic power transmission showing one method of connecting the present invention in the transmission.

Figure 3 is a diagrammatic view of a hydraulic power transmission system incorporating a preferred form of the present invention and showing the parts in one position during operation.

Figure 4 is a diagrammatic view of the same hydraulic power transmission system shown in Figure 3 but showing the parts in another position during operation.

Referring now to Figure 1 there is shown a flowregulating valve [0 comprised of a body 12 having an inlet port M, an outlet port It and a pressure port l8 and containing a compensating valve 20. an adjustable throttle 22 and a pilot valve 24. The ports l4, l6 and I8 are preferably located at the back surface of the body I2 and arranged for connection to the circuit lines by suitable panel mounting" connections, such, for example, as are described in the Martin Patent No. 2,204,507. The body I2 has a main longitudinal stepped bore 26 in communication with inlet port H by means of an inlet passage 28 and with pressure port II! by means of a pressure passage 30. A passage 32 connects bore 26 with throttle 22, and a passage 34 connects throttle 22 with an outlet passage 36 which is in communication with outlet port I3. Throttle 22 is rotatably mounted in a bore 31 which intersects passages 32 and 34, being interposed so as to serve as an adjustable restriction to flow from passage 32 to passage 34.

Tightly inserted in bore 23 is a sleeve 38 positioned therein by a flange 43 of sleeve 38 abutting a shoulder 42 of bore 23. Sleeve 38 has a centrally-located longitudinal bore 44 which is in communication with inlet passage 23 by means of a passage 43, with pressure passage 33 by means of a passage 48, and with passage 32 by means of a passage 53 and a groove Sleeve 38 also has a longitudinally-drilled passageway 52 extending from end to end which is in communication with sleeve passage 53 but not in communication with sleeve passages 43 and 48.

Compensating valve 23 is comprised of a piston 54 provided with a head 33 which is hollow to form a chamber 31. Connected to piston 54 is a stem 38 having a land 33 extending from the right side of piston 34 and a land 32 spaced apart from land 33 and extending to the extreme right end of stem 53. Piston 54 and stem 53 have a longitudinal stepped bore 34 communicating with chamber 31 and extending to a point between lands 33 and 32 where it forms a communication with a transverse passage 33 in stem 53. Compensating valve 23 is inserted in bore 23 of body I2 and bore 44 of sleeve 33 with the right end of land 32 abutting a nipple 31 of a plug 38 which is threaded into the right end of bore 23. This abutment forms a chamber 33 in bore 23 between sleeve 33 and plug 33 with which passage 32 of sleeve 33 is in communication so as to make the effective area on the right side of land 32 responsive to fluid pressure in chamber 33 and also serves the purpose of limiting rightward movement of compensating valve 23.

A chamber I3, formed in bore 23 between the right side of piston 54 and the left end of sleeve 33, is in communication with bore 34 of compensating valve 23 by means of a small drilled passage I2 in land 33 immediately to the right of piston 54. Bore 34 is also in communication with pressure passage 33 by means of another small passage 14 in land 32 spaced apart from passage I2. An inlet chamber I5 is formed in sleeve bore 44 between lands 33 and 32 of valve 23.

Pilot valve 24 is comprised of a spool 13 provided with a land 18 at the extreme right end and a land 83 having a flange 82 spaced apart from land 13. Pilot valve 24 is located in stepped bore 34 of compensating valve 23 with flange 82, which is larger, than bore 64, abutting the left side of piston 54. A chamber 83 is formed in I compensating valve bore 34 between lands I8 and 83 of pilot valve 24. Chamber 83 is always in communication with chamber I3 by means of passage I2. Pressure passage 33 may or may not be in communication with chamber 83 and consequently chamber I3, depending upon whether land 18 of valve 24 is positioned to open or close passage I4.

A spring 34 of predetermined resistance is placedover the left end of spool 13 in chamber 51 abutting the left side of flange 82. A hollow cap 83 threaded into the head 53 of piston 54 forms an abutment for the other end of spring 34, substantially encloses chamber 51, and also limits leftward movement of pilot valve 24.,

A spring88 of predetermined resistance is cated in a chamber-33 formed in bore 23 between piston 54 and a hollow plug 92 threaded into the left end of bore 23. The opposite ends of spring 88 abut piston 54 and plug 92, respectively, so as to normally position compensating-valve 23 in 4 the open pisition shown, with land 32' permitting communication between inlet chamber I3 and passage 33.

A branch passage 84 of passage 34 forms a communication between passage 34 and chamber 33 so as to make compensating valve 23 responsive to the pressure drop across throttle 22. A restricted passage 33 in the head 33 of compensating valve 23 connects chamber 31 with chamber 33 providing a dashpot reaction when pilot valve 24 shifts to the left.

Referring now to Figure 2, there is shown diagrammatically a hydraulic transmission circuit incorporating valve I3. There is shown a pump 33 which may be driven by an electric motor, not shown, which is supplied with fluid from a tank I33 by means of a suction conduit I32 and which is connected to a pressure port I34 of a suitable four-way directional valve I33 by means of a pump delivery conduit I38. There is also shown a motor II3 having a piston II2 connected to which is a piston rod II4, .the head end of said motor being connected to a cylinder port II3 of valve I33 by means of a conduit III and the rod end of said motor being connected to another cylinder port I23 of valve I33 by means of a conduit I 22.

A tank port I24 of valve I33 is connected to the inlet port of valve I3 by means of a return conduit I23. Outlet port I3 of valve I3 is connected to tank I33 by means of a conduit I23. A branch conduit I33 connects pump delivery conduit I38 to the pressure port I8 of valve I3. Inlet port I4, outlet port I3 and pressure port I3 of valve I3 are shown in Figures 1, 3 and 4.

A suitable relief valve I32 is incorporated in the pump delivery conduit I38 and is preferably constructed in accordance with the disclosure of the patent to Harry F. Vickers, No. 2,043,453. Valves of this character may be provided with a venting port for venting the control chamber in order to permit the main valve to act as an unloading valve and bypass the pump delivery at negligible pressure.

A suitable, manually-controlled, two-way control valve I34 is connected by means of a conduit I33 to a venting port I33 of valve I32 and to tank I33 by means of a conduit I 43. In one position control valve I34 will close venting port I38 and permit fluid from pump 33 to flow to directional valve I33 which will direct it to motor H3 in order to start said motor, while in another position control valve I 34 will open venting port I38 to tank I33 by means of conduits I33 and I43, permitting valve I32 to open completely and unload pump 38 to tank I33 by means of an exhaust conduit I42 which connects valve I32 to tank I33, thus stopping motor II3. Relief valve I32 also serves as a safety factor in limiting the maximum pressure able to be developed in the system and in addition cooperates with valve I3 in exhausting to tank I33 an amount of fluid from pump 38 in excess of which throttle 22 has been adjusted to pass.

Referring now to Figures 1 and 3, in operation with the electric motor running and operating pump 93 and with motor II3 stopped by reason of valve I34 being shifted to the position in which venting port I38 of valve I32 is vented to tank I 33 and the full delivery of pump 38 being delivered to tank I33 by means of conduit I42, if valve I34 is shifted to close venting port I38 and directional valve I33 shifted to direct fluid to the head end of motor II3, conduit I33 is connected to conduit I I8 and conduit I 22 to conduit I23. At this stage of the operation, valve I3 will be in the position shown in Figure 1. Fluid under pressure from pump 88 is delivered by means of conduit I08 to the pressure port I04 of directional valve I08 and by means of port I I8 and conduit I I8 to the head end of motor IIO. Pressure fluid from pump 88 is also delivered to the pressure port It of flowregulating valve II) by means of branch conduit I30. Pressure fluid entering pressure port I8 of valve I enters pressure passage 30, passage 48, passage I4, chamber 83, and to chamber I0 by means of passage I2 where pressure fluid acting on the right side of piston 84 shifts valve 20 to the left. Fluid in chamber 80 on the left side of piston 84 may discharge freely by means of passage 8'4, passage 34, outlet passage 38, outlet port It and conduit I28 to tank I00. Shifting of compensating valve 20 to the left by pressure fluid from pump 88 causes land 82 of valve 20 to block passage 50 so that any fluid discharged from motor IIO entering inlet port I4, inlet passage 28, passage 46 and inlet chamber I5 is blocked from communication with throttle 22. Referring now to Figure 4, pressure transmitted from the head end to the rod end of motor I I0 entering inlet chamber I5 enters passage 36 and bore 64 of compensating valve 20 and acts on the right end of land I8 of pilot valve 24, shifting valve 24 to the left. Fluid in chamber 51 being forced out by land 80 of pilot valve 24 must leave by restricted passage 98 in the head 56 of piston 54. This provides a dashpot action which prevents an excessive discharge of fluid from motor H0. Consequentl the movement of piston II2 of motor IIO will be restricted by the dashpot action. When pilot valve 24 has shifted to the left sum'ciently to permit land I8 to block pas sage I4, communication between compensating valve 20 and fluid pressure from pump 98 is blocked. With compensating valve 20 in the position shown in Figure 3 it is almost ready to operate in the well-known manner to maintain a constant flow across throttle 22.

Pressure fluid in chamber 10 may escape by passage 52 to passage 50, and, although the latter is blocked from communication with passage 32 by land 62 of valve 20, fluid in passage 50 may escape by groove 5| to passage 32 and to tank I00 by means of throttle 22, passage 34, outlet pas sage 36, port it and conduit I28.

As shown in Figure 4, dischargingfluid from motor I I0 keeps pilot valve 24 in the closed position, and the escape of fluid from chamber I0 has permitted compensating valve to open partially and permit discharging fluid from mctor M0 to flow across throttle 22 by means of inlet port I4, inlet passage 28, inlet chamber I5, passage 50, groove 5| and passage 32, and thence to tank I00 by means of passage 34, outlet passage 38, port I6 and conduit I28. At the same time, fluid pressure entering passage 50 enters pa'ssage 52 and chamber II! where it may act on the right side of piston 54, and fluid in passage 50 also enters chamber 69 by means of passage 52 where it acts against the right end of land162. Whatever the fluid pressure is beyond throttle 22 in passage 34 is also present in chamber 90 where it may act on the left side of piston 54 and the head 56.

The purpose of compensating valve 20 is to maintain a constant regulated flow across throttle 22. If the pressure drop across throttle 22 is maintained constant, the flow across throttle 22 will be constant. 'Compensating valve 20 is responsive to the pressure drop across throttle 'piston II2 to move.

22, and, if at" any time the pressure in passage 50 builds up due to the restriction of' throttle 22, this increase in pressure also takes place in chamber I0 because of restricted passage 82 forming a means of communication between passage 50 and chamber I0. This pressure increase in chamber I0 which acts on piston 54 causes compensating valve 20 to shift'to the left. Compensating valve 20 shifts only far enough so that land .82 will permit a flow of fluid from inlet chamber I5 to passage 50 in suflicient volume to maintain a predetermined pressure in passage 50. This pressure in passage 50 is determined by the resistance of spring 88. Whatever the pressure existent in conduit I28 is also existent in passage and is communicated to chamber and theleft side of piston by means of passage 94. Thus, by maintaining a constant pressure in passage 50, whi'h pressure is determined by the resistance of spring 88, the flow across throttle 22 will be uniformly constant and the speed of motor I I 0 will be constant. I

If for any'reason the flow of fluid to motor III ceases, pilot valve 24 would shift to the right by action of spring 84. and spring- 88 would open compensating valve 20. When flow from pump 98 to motor H0 is resumed, fluid pressure from pump 98 would again close compensating valve 20, and discharged fluid from motor H0 would have to shift pilot valve -24b'efore compensating valve 20 would be able to operate in the normal manner.

If, upon completion of movement of piston II2 of motor I I0, piston H2 is moved in the opposite direction by shifting valve I06 to connect conduits I08 and I22 and conduits H8 and I26, the same operation is performed. Fluid pressure from pump 98 will close compensating valve 28, and exhaust fluid from the head end of motor IIO must shift pilot valve 24 before compensating valve 20 may operate in a normal manner.

If during a feeding movement the resistance which piston II2 encounters should become too high, the fluid pressure in the motor outlet line I22 will drop below the value of spring 84, and pilot valve 24 will shift to the right. This will cause compensating valve 20 to close as previously described and immediately stop the fluid motor, causing all of the pump delivery to spill over the relief valve I32. Preferably the setting of spring 84 is such as to respond at a relatively low pressure compared to the pressure setting of relief valve I32.

When fluid flow to motor I I0 resumes after interruption, pilot valve 24 will not in any manner interfere with the normal operation of compensating valve 20 after compensating valve 20 assumes normal regulating position. v

If it were not for fluid pressure from pump 88 closing compensating valve 20 when flow was resumed after interruption. compensating valve 20 would be in the completely open position momentarily and permit more fluid to pass through than it would ordinarily allow to pass if it were in regulating position. Before land 82 could shift to partially close communication between inlet chamber I5 and passage 50, an excessive amount of fluid discharged from motor IIO would cause piston II 2 to move at a faster speed for a short distance than the speed at which flow-regulating valve I 0 should permit If motor M0, for instance. was connected to operate a machine cutting .tool, the result would be disastrous to the cutting tool.

It should be noted that the present invention overcomes this temporary lapse of the compensating valve by making it impossible for an amount of fluid above the normal regulated amount to pass through the compensating valve when flow is resumed after interruption.

It should also be noted that compensating valve 20 when in a normal regulating position is never wholly open or wholly closed. Its position fluctuates so as to permit Just enough fluid to enter inlet chamber 15 and to flow through passage 50 which will be suflicient to maintain a constant pressure in passage 50 so as to maintain constant the flow across throttle 22. Whenever flow to the flow regulating valve is interrupted, compensating valve 20 opens completely. When flow is resumed, if the compensating valve remained in this completely open position, a temporary flow of fluid above the normal regulated rate which flow-regulating valve I is originally adjusted to pass would flow through the flow-regulating valve before compensating valve 20 could assume normal regulating position. By momentarily closing the compensating valve when the motor is started after interruption of movement and gradually opening the compensating valve up to normal regulating position, a flow oi' fluid above normal regulated rate through the flow-regulating valve is prevented. By preventing a temporary flow of fluid above normal regulated rate through the flow-regulating valve when the motor is started after interruption, the motor is prevented from jumping, i. e., moving a short distance faster than normal regulated speed of the motor.

While the form of embodiment of the invention as herein disclosed constitutes a preferred form, it is to be understood that other forms might be adopted, all coming within the scope of the claims which follow.

What is claimed is as follows:

1. A flow regulating valve for controlling the flow of fluid in a hydraulic power circuit comprising in combination a flow passage having an inlet and an outlet, an adjustable throttle and a pressure compensating valve in series in said passage, means for operating the compensating valve subjected to pressures in the passage ahead of and beyond the throttle for causing the compensating valve to assume various regulating positions for maintaining the pressure drop across the throttle constant and including means biasing the compensating valve to the fully open position when flow to the inlet of the passage ceases, and a pressure responsive pilot valve hydraulically connected to the operating means and adapted to be connected to an external source of pressure fluid for closing the compensating valve, said pilot valve being responsive to increases 01' pressure at the inlet of the flow passage when fluid flow is resumed to the inlet of the passage after interruption for closing communication between the external source and the operating means and permitting the operating means to cause the compensating valve to assume a regulating position from the fully closed position.

2. A flow regulating valve for controlling the flow of fluid in a hydraulic power circuit comprising in combination a flow passage having an inlet and an outlet, an adjustable throttle and a pressure compensating valve in series in said passage, piston means for operating the compensating valve and responsive to the pressure drop across the throttle for causing the compensating valve to assume various regulating positions for maintaining the pressure drop across the throttle constant and including means biasing the compensating valve to the fully open position when flow to the inlet of the passage ceases, and a pressure responsive pilot valve hydraulically connected to the operating means and adapted to be connected to an external source of pressure fluid for closing the compensating valve, said pilot valve being responsive to increases of pressure at the inlet of the flow passage when fluid flow is resumed to the inlet of the passage after interruption for closing communication between the external source and the operating means and permitting the operating means to cause the compensating valve to assume a regulating position from the fully closed position.

3. A flow regulating valve for controlling the flow oi fluid in a hydraulic circuit and comprising in combination a first passage through which fluid is adapted to flow at a regulated rate, in series in said passage an adjustable throttle and a pressure compensating valve, means for operating the compensating valve responsive to the.

pressure drop across the throttle for causing the compensating valve to assume numerous regulating positions and maintain the pressure drop across the throttle constant and including means biasing the compensating valve to the fully open position when flow to the passage is interrupted, a second passage connected to the operating meansahead of the throttle and adapted to be connected to an external source of pressure, and pressure responsive valve means for controlling the second passage, said valve means being biased to a position opening the second passage for directing pressure to the operating means for closing the compensating valve and being responsive to pressure increases in the flrst passage when fluid flow is resumed to the first passage after interruption for closing communication between the operating means and the external source of pressure thereby permitting the operating means to cause the compensating valve to assume a regulating position from the fully closed position.

4. In a hydraulic power transmission system containing a fluid pump and motor, a flow regulating valve for controlling the speed of the motor, said flow regulating valve comprising in combination a flow passage connected to the motor, in series in the passage an adjustable throttle through which fluid is adapted to flow at a regulated rate and a pressure compensating valve, means for operating the compensating valve responsive to the pressure drop across the throttle for causing the compensating valve to assume numerous regulating positions to maintain the pressure drop across the throttle constant and including resilient biasing means, said resilient means biasing the compensating valve to the fully open position when flow to the flow regulating valve is interrupted, and pressure responsive pilot valve means connected to a source of pressure fluid in the circuit and to the'compensating valve operating means for directing pressure to the operating means for closing the compensating valve, said pilot valve being operatively connected to the operating means ahead 01 the throttle and being responsive to predetermined increases of pressure in the passage when fluid flow is resumed to the passage after interruption for closing communication between the source of pressure and the operating means and permitting the operating means to cause the compensating valve to assume a regulating position from the fully closed position.

5. In a hydraulic power transmission system containing a fluid pump and motor, a flow regulating valve for controlling the speed of the motor, said flow regulating valve comprising in combination a flow passage connected to the motor, in series in the passage an adjustable throttle through which fluid is adapted to flow at a regulated rate and a pressure compensating valve, piston means for operating the compensating valve responsive to the pressure drop across the throttle for causing the compensating valve to assume numerous regulating positions to maintain the pressure drop across the throttle constant and including resilient biasing means, said resilient means biasing the compensating valve to the fully open position when flow to the flow regulating valve is interrupted, a second passage connected to a source of pressure fluid in the circuit and to the piston operating means, and a pressure responsive pilot valve for controlling the second passage operatively connected to the flow passage ahead of the throttle, said pilot valve directing pressure fluid to the piston operating means closing the compensating valve and being responsive to increases of pressure in the flow passage when fluid flow is resumed thereto after interruption for closing the second passage and permitting the operating means to cause the compensating valve to assume a regulating position from the fully closed position.

6. In a hydraulic power transmission system having a fluid pump, a fluid motor and means for stopping the motor by interrupting fluid. flow to the motor, a flow regulating valve for controlling the speed of the motor comprising in combination a flow passage connected to the motor, in series in the passage an adjustable throttle and a pressure compensating valve, piston means for operating the compensating valve responsive to the pressure drop across the throttle for causing the compensating valve to assume numerous regulating positions to maintain a constant pressure drop across the throttle and including resilient biasing means, said resilient means biasing the compensating valve to the fully open position when the motor is stopped and fluid flow to the flow regulating valve is interrupted, and a pressure responsive pilot valve hydraulically connected to a source of pressure in the system and-to the piston operating means, and means biasing the pilot valve to a position connecting the source of pressure to the piston operating means for closing the compensating valve, said pilot valve being responsive to predetermined pressure increases in the flow passage ahead of the throttle when fluid flow is resumed to the motor after interruption for closing the pressure source from the piston operating means and permitting the piston operating means to wause the compensating valve to assume a regulating position from the fully closed position.

FERRIS T. HARRINGTON.

REFERENCES CITED,-

The iollowing references are of record in the flle of this patent:

UNITED STATES PATENTS 

